• Korean Journal of Poultry Science
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• v.47 no.4
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• pp.237-245
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• 2020

This study investigated the effects of breed, laying age, and egg storage period on hatching performance. Eggs were collected from early laying period (27 to 29 weeks old) and late laying period (50 to 52 weeks old) in Hwanggalsaek Jaeraejong, Korean Rhode Island Red, and Korean White Leghorn chicken breeds. Eggs laid for each period were stored for 3, 7 and 14 days and then hatched. Fertility, hatchability, and embryonic mortality were observed to determine the hatching performance. The results showed that hatching performance was affected by breed, laying age, and egg storage period with independently or interactively. The Korean Rhode Island Red breed had the lowest hatching performance. Hatchability and early embryonic mortality rate increased in early laying period eggs compared to the late laying period, but the late embryonic mortality rate increased in late laying period eggs. Additionally, hatching performance decreased as the egg storage period increased. Using breed-specific hatching management techniques, avoiding late laying period eggs, and shortening the egg storage period to seven days after laying may improve the hatching performance.

• KOREAN POULTRY JOURNAL
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• v.33 no.11 s.385
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• pp.63-65
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• 2001

• KOREAN POULTRY JOURNAL
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• v.7 no.10 s.72
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• pp.63-66
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• 1975

양계업의 성공 여부는 산란계 한 마리가 년간 몇 개의 알을 낳느냐에 의하여 결정된다. 일반적으로 산란지수가 많은 계군이 산란피크도 높으므로 더 많은 알을 얻기 위한 방법으로는 산란피크를 향상시켜야 할 것이다. 그러나 아직도 많은 농장에서 보다 빠른수입을 목적으로 또는 관리 부주의로 조산을 시키는 경향이 있다. 조산하게 되면 산란율이 정상적으로 오르지 못하므로 30$\~$33주령이 되어도 산란피크가 보잘 것 없게 되며 이때야 비로소 여러 가지 방법을 강구하지만 이미 닭의 산란능력이 결정되었으므로 보다 좋은 성적은 기대하기 어렵다. 닭의 산란생리는 일단 산란피크에 도달한 다음 산란율이 일정한 비율로 서서히 떨어지게 되어 있다. 그러므로 산란피크가 얼마나 올라가느냐는 장차 계군이 몇 개의 알을 생산할 수 있는가를 예측하는 기준이 될 수 있다.

• Korean Journal of Poultry Science
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• v.19 no.2
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• pp.77-95
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• 1992

This study was conducted to provide a guideline for laying hens breeding through comparing performance test results and domestic and foreign breeding processing for the purpose of succeeding in laying hen industry. The annual average egg numbers were 120 at 1930, 135 at 1940 and 175 at 1950 which was 146% increase during a decade. Heterosis was firstly introduced at 1924 and was applied to produce commercial stock since 1950. The theory of selection for quantitative traits was established by Lerner in 1951. In Europe and America, the annual average egg numbers in performance test were 175, 213, 219 and 277 in 1950, 1960, 1970 and 1985, respectively, and in Korea, those were 196, 226 and 265 in 1960, 1970 and 1980, respectively Laying hen breeding through simultaneous selection of numerous traits may provoke elevation of viability, improvement of feed efficiency, alongation of laying period and increase of disease resistance.

• KOREAN POULTRY JOURNAL
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• v.11 no.6 s.116
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• pp.144-145
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• 1979

• KOREAN POULTRY JOURNAL
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• v.42 no.2
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• pp.103-107
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• 2010

• KOREAN POULTRY JOURNAL
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• v.52 no.10
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• pp.118-121
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• 2020

뛰어난 사양 성적을 내기 위해 많은 농가들이 노력하고 있으나, 다향한 내·외부 요인들을 관리하며 높은 사양 성적을 유지하기란 쉽지 않다. 그에 따라 생산성을 제고하기 위한 농가들만의 다양한 방법이 존재한다. 본지는 우수한 성적으로 축산농가의 모범이 되는 대표농가로 선정되어 높은 생산성을 인정받은 형제농장의 김동남, 허영신 부부를 만나 그들의 농장 운영 비법을 들어보았다.

• Korean Journal of Ichthyology
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• v.7 no.1
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• pp.18-24
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• 1995

The spawning condition was investigated of the bitterling, Acheilognathus yamatsutae Mori in aquariums. Sexual responses in male and female bitterlings were very sensitive to the mussel rather than the other sex. But spawning behavior was shown ouly when all of the male, the female and the mussel were present. And the sexual response was not shown at all when there was no direct contact with the live mussel.

• Korean Journal of Ichthyology
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• v.29 no.3
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• pp.176-189
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• 2017

Age estimation and sexual dimorphism of Coreoleuciscus splendidus were estimated using otolith, length-frequency distribution and 23 morphological measurements, from 245 individuals collected from September 2016, February and April 2017 in the Gapyeong stream, Han River, Korea. Result of age estimation of C. splendidus, we most examined were 2, 3 and 4-age, and the maximum observed ages were 5-age. Nine out of twenty-three morphometric measurements were significantly different between the genders. Anal fin have showing major sexual dimorphism in particular between adult individuals. This sexual dimorphism was based on extension of anal fin soft rays of male individuals. Therefore anal fin of males is always longer and wider than females. During spawning season male individuals possess nuptial tubercles on anal fin rays. However, another measurements and morphological characters does not exhibit sexual dimorphism in the between male and female individuals. The sexual dimorphism was observed to only over 2-years old individuals with sexual maturity. But juvenile and 1-years old individuals do not have sexual dimorphism with sexual maturity. Peak season of spawning was April to May and they start first spawning at 2-age. The ages at major spawning groups were most 3-age, and they maximum GSI index was 14.91 (female), 8.96 (male) at 5-age, respectively.

• KOREAN POULTRY JOURNAL
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• v.53 no.10
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• pp.124-127
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• 2021

고병원성 AI 발생, 계란 살충제 파동, 저난가 시대 등 지난 3년간 산란계 산업에 많은 어려움들이 있었다. 이러한 어려움 속에서도 30년 넘게 양계업을 해오며 높은 산란 성적률을 보여주며 2대를 이은 농장 운영으로 탄탄한 사육 현장을 보여주고 있는 충남 아산시 소재의 신창농장의 김병규 대표를 찾았다.